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/* filter_vsx_intrinsics.c - PowerPC optimised filter functions
*
* Copyright (c) 2016 Glenn Randers-Pehrson
* Written by Vadim Barkov, 2017.
* Last changed in libpng 1.6.25 [September 1, 2016]
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*/
#include <stdio.h>
#include <stdint.h>
#include "../pngpriv.h"
#ifdef PNG_READ_SUPPORTED
/* This code requires -maltivec and -mabi=altivec on the command line: */
#if PNG_POWERPC_VSX_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
/* libpng row pointers are not necessarily aligned to any particular boundary,
* however this code will only work with appropriate alignment. arm/arm_init.c
* checks for this (and will not compile unless it is done). This code uses
* variants of png_aligncast to avoid compiler warnings.
*/
#define png_ptr(type,pointer) png_aligncast(type *,pointer)
#define png_ptrc(type,pointer) png_aligncastconst(const type *,pointer)
/*#include <altivec.h>*/
#if PNG_POWERPC_VSX_OPT > 0
void png_read_filter_row_up_vsx(png_row_infop row_info, png_bytep row,
png_const_bytep prev_row)
{
png_size_t i;
png_size_t istop = row_info->rowbytes;
png_bytep rp = row;
png_const_bytep pp = prev_row;
for (i = 0; i < istop; i++)
{
*rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
rp++;
}
}
void png_read_filter_row_sub4_vsx(png_row_infop row_info, png_bytep row,
png_const_bytep prev_row)
{
png_size_t i;
png_size_t istop = row_info->rowbytes;
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
png_bytep rp = row + bpp;
PNG_UNUSED(prev_row)
for (i = bpp; i < istop; i++)
{
*rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
rp++;
}
}
void png_read_filter_row_sub3_vsx(png_row_infop row_info, png_bytep row,
png_const_bytep prev_row)
{
png_size_t i;
png_size_t istop = row_info->rowbytes;
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
png_bytep rp = row + bpp;
PNG_UNUSED(prev_row)
for (i = bpp; i < istop; i++)
{
*rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
rp++;
}
}
void png_read_filter_row_avg4_vsx(png_row_infop row_info, png_bytep row,
png_const_bytep prev_row)
{
png_size_t i;
png_bytep rp = row;
png_const_bytep pp = prev_row;
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
png_size_t istop = row_info->rowbytes - bpp;
for (i = 0; i < bpp; i++)
{
*rp = (png_byte)(((int)(*rp) +
((int)(*pp++) / 2 )) & 0xff);
rp++;
}
for (i = 0; i < istop; i++)
{
*rp = (png_byte)(((int)(*rp) +
(int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
rp++;
}
}
void png_read_filter_row_avg3_vsx(png_row_infop row_info, png_bytep row,
png_const_bytep prev_row)
{
png_size_t i;
png_bytep rp = row;
png_const_bytep pp = prev_row;
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
png_size_t istop = row_info->rowbytes - bpp;
for (i = 0; i < bpp; i++)
{
*rp = (png_byte)(((int)(*rp) +
((int)(*pp++) / 2 )) & 0xff);
rp++;
}
for (i = 0; i < istop; i++)
{
*rp = (png_byte)(((int)(*rp) +
(int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
rp++;
}
}
void png_read_filter_row_paeth4_vsx(png_row_infop row_info,
png_bytep row,
png_const_bytep prev_row)
{
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
png_bytep rp_end = row + bpp;
/* Process the first pixel in the row completely (this is the same as 'up'
* because there is only one candidate predictor for the first row).
*/
while (row < rp_end)
{
int a = *row + *prev_row++;
*row++ = (png_byte)a;
}
/* Remainder */
rp_end = rp_end + (row_info->rowbytes - bpp);
while (row < rp_end)
{
int a, b, c, pa, pb, pc, p;
c = *(prev_row - bpp);
a = *(row - bpp);
b = *prev_row++;
p = b - c;
pc = a - c;
#ifdef PNG_USE_ABS
pa = abs(p);
pb = abs(pc);
pc = abs(p + pc);
#else
pa = p < 0 ? -p : p;
pb = pc < 0 ? -pc : pc;
pc = (p + pc) < 0 ? -(p + pc) : p + pc;
#endif
if (pb < pa) pa = pb, a = b;
if (pc < pa) a = c;
a += *row;
*row++ = (png_byte)a;
}
}
void png_read_filter_row_paeth3_vsx(png_row_infop row_info,
png_bytep row,
png_const_bytep prev_row)
{
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
png_bytep rp_end = row + bpp;
/* Process the first pixel in the row completely (this is the same as 'up'
* because there is only one candidate predictor for the first row).
*/
while (row < rp_end)
{
int a = *row + *prev_row++;
*row++ = (png_byte)a;
}
/* Remainder */
rp_end = rp_end + (row_info->rowbytes - bpp);
while (row < rp_end)
{
int a, b, c, pa, pb, pc, p;
c = *(prev_row - bpp);
a = *(row - bpp);
b = *prev_row++;
p = b - c;
pc = a - c;
#ifdef PNG_USE_ABS
pa = abs(p);
pb = abs(pc);
pc = abs(p + pc);
#else
pa = p < 0 ? -p : p;
pb = pc < 0 ? -pc : pc;
pc = (p + pc) < 0 ? -(p + pc) : p + pc;
#endif
if (pb < pa) pa = pb, a = b;
if (pc < pa) a = c;
a += *row;
*row++ = (png_byte)a;
}
}
#endif /* PNG_POWERPC_VSX_OPT > 0 */
#endif /* PNG_POWERPC_VSX_IMPLEMENTATION == 1 (intrinsics) */
#endif /* READ */
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